You have to understand that even though you are only the communications guy and have far less actual combat experience than your teammates, for some reason normal world physics don't seem to apply to you. In fact, you don't even seem to be in control of your own actions. Instead, it feels like you are in a game, with crappy graphics but awesome gameplay, and someone is controlling you. I just hope that person knows what he/she is doing, for your sake.
on topic: Nice guess Anticheese! Did you test it? Cause i have, and everything pointed to that formula. But since some variables always remain unknown, i could never be sure.
One of the interesting things about how armor works is how it affects the damage that you can do against the CD for example. It explains why even overcharged plasma rifles seem to have hardly any effect on him, while one rocket at least damages him a bit.
It also explains why Arachnotrons look like the worst enemy at first glance, but you will come to fear the Cacodemon the most in time